That is because these engines can't be broken-in with any WOT method...I tried it myself with my first JLR, and didn't last much without it giving me problems. The Picco Evo2 Edo. I gtot afterwards I run it in according to Picco's instructions and made a world of difference. These engines don't have the traditional high pinch that other engines have, so it needs very little time to break-in.
Don’t confuse compression with pinch; Sleeve Pinch is not that important contrary to popular belief. The question is how well it seals as soon as the piston starts to close the exhaust port and if it holds compression after you roll it to top dead center.
Place a few drops of after run oil trough the top (removing plug), then place plug in place, then roll piston to top dead center and listen and look for air bubbles through exhaust port. If there’s none, then your engine still has compression, even if it has no pinch.


RUN-IN

Proper run-in of the engine is a very important step in ensuring that you get the highest performance and lifetime of your engine. Take your time for proper run-in. Do not use run-in benches, but use your car for run-in. Use the same fuel as you will be using for the life of the engine.
Special run-in fuel is not needed. If your engine doesn’t start easily you may try loosen the glow plug by ˝-turn to decompress the engine and try again. Don’t forget to tighten the glow-plug
again once the engine started!
Procedure:
• Start the engine and set the main-needle very rich, i.e. excessive smoke coming from the muffler.
• Let the engine idle for 2mins first to warm it up.
• Now start driving your car, it will be slow and sluggish, but this is an important step.
• Do not allow the engine to rev-up too high, run the engine at half speed on the straightaway.
• The engine should not be too cold and not too hot during run-in, 70-80°C (160-180°F) is perfect.
• Let the engine cool down for 15mins after each tank during the run-in period.
• We recommend doing so for 5 tanks of fuel before you start tuning your engine.

Regarding carburator: Don't use Nova carbs you will have flame out problems due to excesive temp on body. These engines need composite bodied carbs (Sirio, STS).

Tuning the engine: I agree 100% with RayJ's findings, that is how i run it.
I run the LSN very rich at 8 to 8.5 turns out. This coupled with running the clutch to the point where it slips, then just back it enough so the clutch doesn't slip,eliminates any lean bogging the engine had. Then just tune your HSN accordingly for top speed.

AFM